The Trotters beat off competition from local rivals Wigan Athletic and Blackburn Rovers to land the 29-year-old, who made just four appearances for the German outfit in six months.
Bolton boss Owen Coyle has said that he is delighted to have secured the services of a proven Premier League player.
"Bolton Wanderers are delighted to have secured the loan for Tuncay," he told the club's official website.
"He has great experience added to the proven quality he possesses. We are pleased to have brought him to our club."
The Turkish international will be unavailable for the club's trip to Loftus Road in the first game of the season, as he is still awaiting his work permit.